Paclobutrazol and potassium nitrate were applied for two seasons (2002 and 2003) on Ewais and Sidik mango cultivars to evaluate their effect on leaves content of nitrogen, carbohydrates and C/N ratio. Trees were sprayed with potassium nitrate in October at 1, 2 and 4 % in the two seasons , meanwhile pacloputrazol was used only in the first season as a soil drench at 2.5, 5 and 7.5 g per tree. The treatments were carried out on “on year" trees in the first season. KNO3 and PBZ increased leaves carbohydrates content of both Ewais and Sidik mango cultivars and there was a direct relationship between the used concentrations and this content. Using PBZ at 7.5 g per tree and KNO3 at 4% significantly increase carbohydrates content in the leaves for both tested cultivars. Regardless of treatments the leaves total carbohydrates content increased significantly during Nov. and Dec. as it reached their maximum level, then it decreased sharply from Jan. to Feb. and increased again in Mar.                 Increasing KNO3 and PBZ concentration increased leaves nitrogen content. The application of PBZ at 7.5 g per tree and KNO3 at 4% significantly increased this content compared to the control. The highest leaves nitrogen content was recorded in Nov. with PBZ at 7.5 g per tree and KNO3 at 4%, then gradually decreased and attained the lowest level in Jan. and Feb., afterwards an increase occurred during March.        C/N ratio was significantly increased with the application of KNO3 and PBZ at all tested concentrations, except low levels of PBZ on Sidik cv. at the second season. There was a direct relationship between the used concentration and this ratio.